Users Guide

Related Concepts
Number Of Physical Disks Per Virtual Disk
Virtual Disk Considerations On Systems Running Linux
On some versions of the Linux operating system, the virtual disk size is limited to 1TB. Before creating a
virtual disk that is larger than 1TB, you should make sure that your operating system supports this virtual
disk size. The support provided by your operating system depends on the version of the operating system
and any updates or modifications that you have implemented. In addition, you should investigate the
capacity of your peripheral devices to support a virtual disk that is larger than 1TB. For more information,
see your operating system and device documentation.
Number Of Physical Disks Per Virtual Disk
There are limitations on the number of physical disks that can be included in the virtual disk. These
limitations depend on the controller. When creating a virtual disk, the controllers support some stripes
and spans (methods for combining the storage on physical disks). Since, the number of total stripes and
spans is limited, the number of physical disks that can be used is also limited. The limitations on stripes
and spans affect the possibilities for concatenation and RAID levels as follows:
• Maximum number of spans affects RAID 10, RAID 50, and RAID 60.
• Maximum number of stripes affects RAID 0, RAID 5, RAID 50, RAID 6, and RAID 60.
• Number of physical disks in a mirror is always 2. This property affects RAID 1 and RAID 10.
If RAID 50 and RAID 60, you can use a greater number of physical disks than is possible for other RAID
levels. RAID 10 on a SAS controller with firmware version 6.1 can use a maximum of 256 physical disks.
However, the number of connectors on the controller imposes limitations on how many physical disks
can be included in a virtual disk when using RAID 10, RAID 50, or RAID 60. This is because only a limited
number of physical disks can be physically attached to the controller.
For information about the maximum number of physical disks supported by a virtual disk, see the virtual
disk specifications for the controller in Supported Features.
Related Concepts
Virtual Disk Considerations For PERC S100, S110, S130, And S300 Controllers
Number Of Virtual Disks Per Controller
There are limitations on the number of virtual disks that can be created on the controller. For information
about the maximum number of virtual disks supported by a controller, see the virtual disk specifications
for the controller in Supported Features.
Calculation For Maximum Virtual Disk Size
The Create Virtual Disk Express Wizard displays the minimum and maximum values for the virtual disk
size. This section describes how the maximum possible size for the virtual disk is calculated based on the
controller type. To identify the controller type, see RAID Controller Technology: SATA and SAS.
SATA RAID Controllers
When using a SATA RAID controller, the controller calculates the maximum virtual disk size based on your
RAID level selection and the available physical disk space provided by all suitable physical disks attached
to the controller. For example, if the controller contains 12 physical disks with available space and you
143